Electric shavers may have one or more cutter elements driven by an electric drive unit in an oscillating manner where the cutter elements reciprocate under a shear foil, wherein such cutter elements or undercutters may have an elongated shape and may reciprocate along their longitudinal axis. Other types of electric shavers use rotatory cutter elements which may be driven in an oscillating or a continuous manner. The said electric drive may include an electric motor or a magnetic type linear motor, wherein the drive unit may include an elongated drive transmitter for transmitting the driving motion of the motor to the cutter element.
Such drive systems are sometimes quite complex in structure due to the fact that, in addition to the aforementioned cutting motion, the cutter elements may be movable in other directions so as to adapt to the contour of the skin to be shaved. For example, the cutter elements may be part of a shaver head that is pivotably supported relative to the shaver housing, wherein the pivot axis of such shaver head may extend transverse to the longitudinal direction of the shaver housing. In addition or in the alternative to such shaver head movements, the cutter elements may be movably supported relative to the shaver head so as to adjust their position relative to the skin.
For example, US 2009/0025229 A1 discloses an electric shaver having a shaver head pivotably supported relative to the shaver housing about a shaver head pivot axis extending transverse to the longitudinal axis of the shaver housing. A pair of cutter elements provided under a shear foil can be driven in an oscillating manner along a cutter oscillation axis substantially parallel to said shaver head pivot axis. To transmit the driving action of an electric motor accommodated in the shaver housing to the cutter elements, the drive unit includes transmitter pins extending from the shaver housing towards the shaver head, wherein the oscillating driving movements of said transmitter pins are applied onto the cutter elements via an oscillatory bridge supported for oscillatory reciprocation in said shaver head, wherein said oscillatory bridge includes yielding coupling arms so as to compensate for the adjusting movements of the cutter elements. Due to the rather complex shape of the oscillatory bridge, however, the transmission architecture is rather complicated. Moreover, the yielding structure of the oscillatory bridge is power-consuming and detrimental to achieving high frequencies of oscillation of the cutter elements.
A similar transmission architecture including an oscillation bridge of a pivoting type is known from U.S. Pat. No. 7,841,090 B2.
Self-adjusting movements of the cutter elements to adapt to the skin contour becomes more difficult when the shaver head includes auxiliary function elements such as a cooling element for cooling the skin to be shaved or lubricating elements for lubricating the skin to be shaved. Such non-cutting auxiliary function elements do not only require additional space in the shaver head, but sometimes interfere with the desired movability of the cutter elements. The auxiliary function elements have sometimes application heads positioned close to or adjacent to the cutter elements so as to contact the skin portion to be shaved or apply the auxiliary function thereto, wherein it is sometimes desirable that the auxiliary function element does not participate in the self-adjusting movements of the cutter elements. For example, it is sometimes desirable to have a rigidly supported auxiliary function element that can be pressed against the skin with a higher pressure than the cutter elements. Furthermore, movably supporting the auxiliary function elements to allow self-adjustment in a way similar to the cutter elements renders the shaver head even more bulky and makes it difficult to connect the auxiliary function elements to supportive components such as thermal elements like Pelletier elements or storage elements like lubricant tanks.
WO 2010/003603 A1 describes an electric shaver having a cooling element as an auxiliary function element, wherein said cooling element includes rib-shaped contact portions extending along the cutter elements on an outer side of the shaver head and between said cutter elements. The cutter elements are supported against said cooling element by means of springs so that the cutter elements may dive in a direction substantially parallel to the longitudinal axis of the shaver housing, i.e. the cutter elements may dive into the shaver head due to skin contact pressure. Aside from such diving movements, however, the cutter elements may not execute any other self-adjusting movements and the entire shaver head is rigidly held in position due to the fixedly positioned cooling elements.